DESCRIPTION: The grant proposes to study T cell population dynamics in a series of SIV non-infected and SIV infected primates to include both AIDS sensitive rhesus macaques and AIDS resistant sooty mangabeys (SMMs). A primary goal will be to assess the validity of current methodologies used to study T cell turnover by direct comparison of T cell turnover rates generated using stable isotope/mass spectrometric analysis (SI/MS) of deuterated [6,6-2H2] glucose incorporation, BrdU labeling and Ki67 expression. Furthermore, comparison of T cell turnover rates in peripheral blood vs. secondary lymphoid tissues will be measured in the presence and absence of retroviral infection.